Factoring in that the prison population is a "good chunk" of the total population should elevate the scale of this discussion above statistical haggling

Total incarcerated population is about 2.3M

State Level: 1.3M * 1.6% = 20,800 Federal: 225k * 2.2% = 4,950

So about 25k people out of a country of 330M (0.007%)

And most of these are for trafficking, not just possession.

I still think it's too many people, but it's not a "good chunk." The amount of people that actually go to jail for mere possession is tiny, and that number is going down.

You can't say "state prison population" and not specify which state, unless I'm misunderstanding?

I think it means population of all the state prisons combined.